Originally posted by wlachan Officially, its failure rate is no more than usual, whatever that means.
That's almost as obscure as "It's failure rate is no more than expected."
There are lots of posts about people overjoyed with their equipment here and on other forums. This dismissal of problems by blaming the person for complaining (however obliquely) just doesn't wash. I don't see posts about failures in the 55-300, or the limited primes (which cost less than the SDM zooms), or many other Pentax products. I do see complaints about the SDM Zooms and the K-r. It seems clear that they have issues beyond normal production and quality issues. Some have posted about having the same SDM lens fixed several times, are they just whiners?
Those charts make my point for me. The 18-135
DC has how many failures? Out of 100 or so, precisely 0. The 17-70
SDM has how many failures reported? Out of 80 or so, there are around 34 or so - a 42.5% failure rate. Are there SDM lenses that fail less often, yes and to be fair among the zooms the 60-250 (which is the most expensive) fails the least. But the point is that they fail, and at an astonishing rate - particularly given the princely sums demanded for them.